<h2>题目编号 : 173</h2>
<div style="color:#666;font-size:80%;">22 December 2007</div><br />
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<p>We shall define a square lamina to be a square outline with a square &quot;hole&quot; so that the shape possesses vertical and horizontal symmetry. For example, using exactly thirty-two square tiles we can form two different square laminae:</p>
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<img src="project/images/p_173_square_laminas.gif" alt="" />
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<p>With one-hundred tiles, and not necessarily using all of the tiles at one time, it is possible to form forty-one different square laminae.</p>
<p>Using up to one million tiles how many different square laminae can be formed?</p>
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